1. Field of the Invention
The invention relates to an image forming device, an image forming method, and a computer readable recording medium stored with an image forming program. The invention relates to an image forming device, in particular, such a device capable of supporting paper to be discharged to a paper tray by carrying it on said paper tray, an image forming method, and a computer readable recording medium stored with an image forming program.
2. Description of the Related Art
A large amount of printed paper is discharged onto a paper tray in an image forming device capable of a large amount of printing.
When paper of a larger size is discharged after a large amount of paper of a smaller size is discharged in such an image forming device, a portion of the larger size paper that sticks out from the surface of the paper of the smaller tends to bend downward due to gravity. If the paper bent as such is left for a while on the paper tray, the paper may create a permanent deformation or a crease.
Therefore, the user is forced to do a cumbersome work of constantly watching the paper tray of the image forming device and removing paper left on the paper tray in order to prevent the formation of permanent bends or creases when paper of a plurality of sizes is to be discharged on the paper tray in large quantities.
As a technology of preventing the bend of paper discharged on the paper tray, an image forming device capable of controlling a mechanical stopper that dictates the positioning of sheets being discharged on the paper tray is disclosed (see Unexamined Publication No. JP-A-2000-255882). However, this image forming device intends to prevent the bending of sheets of paper by stopping the motion of the mechanical stopper when it detects the sheets of paper while moving the mechanical stopper in the direction opposite to the direction of paper discharge. Consequently, this image forming device only prevents the bending of sheets of paper caused by abutting of the mechanical stopper against the sheets of paper so that it is incapable of preventing the bending of larger size paper discharged on top of smaller size paper.
Also, a sheet post-processing device has been disclosed for straitening sheets of paper by pressing the end of the sheets of paper discharged on paper tray in accordance with the sheet size (see Unexamined Publication No. JP-A-5-8581). However, this sheet post-processing device is not capable of preventing the bending of larger size paper discharged on top of smaller size paper as it simply intends to prevent damages of the sheets by pressing on the end of the sheets with a constant force regardless of the sheet size while straightening out the sheets.
Also, an image forming device is disclosed by inserting a separating sheet of paper in front of each file when a multiple files are being printed (see Unexamined Publication No. 2001-301245). However, this image forming device simply separates each file of printed matters irrespective of the size of paper used for printing and does not disclose a method of preventing the bending or creasing of paper.